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oracle 减少心跳流量,为何而心跳

2.检查bdump目录下生成的跟踪文件

目录在$ORACLE_HOME/admin/$ORACLE_SID/bdump目录下，每个后台进程都会生成一个跟踪文件。

[oracle@jumper bdump]$ ls

20050424_alert_conner.log  conner_arc0_2569.trc  conner_dbw0_2559.trc  conner_reco_2567.trc

alert_conner.log           conner_arc1_2571.trc  conner_lgwr_2561.trc  conner_smon_2565.trc

a.sql                      conner_ckpt_2563.trc  conner_pmon_2557.trc

3.检查CKPT进程的跟踪文件

我们可以很容易的发现CKPT进程每3秒都对控制文件进行一次写入

[oracle@jumper bdump]$ tail -f conner_ckpt_2563.trc

WAIT #0: nam='rdbms ipc message' ela= 2994710 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2442 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2995171 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2586 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2994962 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2582 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2995020 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2455 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2995188 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2412 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2995187 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2463 p1=3 p2=3 p3=3

WAIT #0: nam='rdbms ipc message' ela= 2995095 p1=300 p2=0 p3=0

WAIT #0: nam='control file parallel write' ela= 2448 p1=3 p2=3 p3=3

4.检查控制文件的变更

通过2次dump控制文件，比较其trace文件输出可以比较得到不同之处，我们发现，Oracle仅仅更新了Heartbeat这个数值。

[oracle@jumper udump]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Wed Jan 18 22:44:10 2006

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production

With the Partitioning option

JServer Release 9.2.0.4.0 - Production

SQL> alter session set events 'immediate trace name CONTROLF level 10';

Session altered.

SQL> exit

Disconnected from Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production

With the Partitioning option

JServer Release 9.2.0.4.0 - Production

[oracle@jumper udump]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Wed Jan 18 22:44:18 2006

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production

With the Partitioning option

JServer Release 9.2.0.4.0 - Production

SQL> alter session set events 'immediate trace name CONTROLF level 10' ;

Session altered.

SQL> exit

Disconnected from Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production

With the Partitioning option

JServer Release 9.2.0.4.0 - Production

[oracle@jumper udump]$ ls

conner_ora_21896.trc conner_ora_21898.trc

[oracle@jumper udump]$ diff conner_ora_21896.trc conner_ora_21898.trc

1c1

< /opt/oracle/admin/conner/udump/conner_ora_21896.trc

---

> /opt/oracle/admin/conner/udump/conner_ora_21898.trc

14c14

< Unix process pid: 21896, image: oracle@jumper.hurray (TNS V1-V3)

---

> Unix process pid: 21898, image: oracle@jumper.hurray (TNS V1-V3)

16c16

< *** SESSION ID9.813) 2006-01-18 22:44:14.314

---

> *** SESSION ID9.815) 2006-01-18 22:44:21.569

63c63

< heartbeat: 579991793 mount id: 3191936000

---

> heartbeat: 579991796 mount id: 3191936000

[oracle@jumper udump]$

In 8.0.5 a heartbeat mechanism was included in CKPT's timeout action (every 3 seconds) to update the checkpoint progress record for the thread in the controlfile.

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